On Thu, Oct 6, 2011 at 03:10, Shlomi Fish <[email protected]> wrote:
> Furthermore, I think you can only put when inside given and not arbitrary
> code,
> and that "when()" operates on the datum that was given to given().
I don't think there's any restriction on what code can be inside the
'given' block -- at least, there's nothing in 'perlsyn' saying you
can't have other code in there.
You are correct that 'given()' sets up a (lexically scoped, I guess?)
$_ equal to the argument that it is given -- which is a copy, not an
alias -- and the smart matches in when() will then use that $_ -- but
if you have a 'when()' that doesn't check $_, then you're fine. See
sample code below.
Note: that is not say that any of this is *advisable* -- it's not,
unless you really really need to. (You don't really really need to, in
case you're wondering.) You're probably better off only having
'when()' blocks inside a 'given()' block, and you're probably better
off keeping the conditions in your 'when()' tests nice and simple.
You'll thank yourself down the road.
Sample code:
#! /usr/bin/env perl
use strict;
use warnings;
use feature 'switch';
$_ = 'outside';
my $foo = 'foo';
given( $foo ) {
when( 1 == 1 ) { print "INIT\n" ; continue }
when( 'bar' ) { print "BAR: $foo $_\n" }
$foo = 'bar';
when( 'foo' ) { print "FOO: $foo $_\n" }
$foo = 'baz';
when( 'outside' ) { print "OUT: $foo $_\n" }
default { print "DEF: $foo $_\n" }
}
print;
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